Depends what you mean by spirituality. Ken Wilber describes a system of “wake up, grow up, clean up, show up.” In terms of the first dimension - awakening the mind to its true/original nature of non-dual awareness - easterners have far out-developed westerners in this regard. However in the other dimensions it’s less clear and possible to argue westerners are more developed in these other dimensions. For example in the East i don’t think you’ll find anything near Jung’s work and subsequent psychology for cleaning up. So it depends how you define spiritual advancement.

In Wilber’s system he describes the follies of advanced waking up without growing up (the many scandals re sex money & power), a thing that’s common in cultures that have spiritual gurus.

I don't know if I fully agree with that. It's more like they have a much stronger and more cohesive spiritual lineage to draw on, so that their starting point is where many of us find ourselves only after years of struggle.

Doesn't make it more right or better, and it doesn't by default mean that they are on the right path, only that it's more likely that they are.

Besides, taking your first step on the "right" path as a free action of your own heart is better and more valuable than a million years of knowledge carrying you towards enlightenment, right?